Colorado dinosaur discovery – Tyrannosaurus rex

Tyrannosaurus rex skeleton
This Tyrannosaurus rex skeleton was recovered from Wyoming and is displayed at the Carnegie Museum of Natural History in Pittsburgh. | Photo by Joshua Franzos for Carnegie Museum of Natural History


The first known specimen of Tyrannosaurus rex was a 3.5-inch, banana-shaped tooth that Golden schoolteacher Arthur Lakes found on South Table Mountain near Golden.

Golden civic leader Edward Berthoud sent a sketch of the tooth in an 1874 letter to paleontologist Othniel Marsh, but the tooth was not identified as coming from a Tyrannosaurus for more than a century.

Partial skeletons of the giant meat-eater had to be unearthed in Wyoming and Montana before H.F. Osborn, president of the American Museum of Natural History in New York, was able to name and describe the dinosaur in 1905.

The tooth was determined to belong to a T. Rex when it was re-examined by paleontologist Kenneth Carpenter of the Denver Museum of Nature & Science in 2002.

The Tyrannosaurus Rex, also known as “T. rex,” lived in the Cretaceous period about 65 million years ago and featured a massive head and a long, heavy tail. The dinosaur walked on two hind legs but held its body parallel to the ground, with the tail extended to balance the head. It had short arms, each with two claws.

The Tyrannosaurus measured up to 42 feet in length, stood up to 13 feet tall at the hips and weighed 6 to 7 1/2 tons, making it larger than the Allosaurus from the Jurassic period.

Paleontologists have long debated whether the Tyrannosaurus was a predator or merely a scavenger.